Apparatus for controlling the operation of a machine, locking insert for such an apparatus, and associated method of operation

ABSTRACT

The invention relates to an apparatus ( 1 ) for controlling the operation of a machine ( 3 ), comprising a device for monitoring the status of a safety device ( 2 ) for the machine ( 3 ), in particular a safety switch for monitoring the closed status of a safety gate or similar of the safety device ( 2 ), wherein when the safety device ( 2 ) is in the closed state, the apparatus ( 1 ) can provide an enabling signal for operation of the machine ( 3 ), characterized in that the apparatus ( 1 ) has a detection device ( 10 ) for detecting a locking insert ( 14 ), which insert can be effectively connected to the detection device ( 10 ), is portable, and can be removed from the detection device ( 10 ) without the use of a tool, and in that even when the safety device ( 2 ) is in the closed state, the apparatus ( 1 ) will provide the enabling signal only if the locking insert ( 14 ) is effectively connected to the detection device ( 10 ). The invention further relates to a locking insert ( 14 ) for such an apparatus ( 1 ) and to an associated method of operation.

The present invention relates to an apparatus for controlling the operation of a machine, a locking insert for such an apparatus as well as a method of operation of such an apparatus.

Such apparatuses have a device for monitoring the status of a safety device for the machine, in particular a safety switch for monitoring the closed status of the safety gate or the like of the safety device. When the safety device is in a closed state, the apparatus can provide an enabling signal for the operation of the machine. When the safety device is in an opened state, the safety switch interrupts one or more circuits, for example by means of an electrical contact pair that is actuated by means of positive locking, or by means of an electronic switching element. The enabling signal is then no longer provided. The associated machine is thereby transferred to a secure operational state, for example shut down, or a startup of the machine is prevented.

A safety switch is known from EP 0 801 801 A1, in which a mechanically encoded actuator can be inserted in a switch head, upon which a control gear rotates, and the control gear actuates an electrical switch by means of a plunger.

A safety switch is known from DE 197 11 588 A1, having a reading head and an electronically encoded actuator, each of which have a first or second electronic assembly respectively having electrical and/or electronic components, which can be brought into interaction with one another without an electrical contact and thereby control the safety switch.

For safety switches having a mechanically encoded actuator, so-called blocking inserts are known, which are inserted into the switch head of the safety switch, and which can be secured there against unauthorized removal. When the locking insert is inserted, it is no longer possible to insert the actuator into the switch head, so that the safety switch prevents the machine disposed inside the safety device from starting up, either directly, or by means of a superordinate control device. Such blocking inserts may be used by machine technicians, for example, so that, when entering the space within the safety device, they can prevent the machine from being made operational when the safety device is closed. For this purpose, the blocking inserts can also be fixed to the switch head by means of U-locks.

A safety control and a method for controlling an automated system is known from DE 10 2008 060 010 A 1.

An apparatus for monitoring the status of a safety device of a machine is known from DE 10 2008 055 685 A 1.

The object of the present invention is to provide an apparatus for controlling the operation of a machine, a locking insert for such an apparatus, as well as a method of operation for such an apparatus, which reliably prevents an unintentional startup of the machine, or a startup of the machine that is impermissible for safety reasons, and that are thereby also easy to handle taking into account the environmental conditions that prevail at the manufacturing facility.

This object is achieved by the apparatus defined in claim 1, as well as by the locking insert and method of operation defined in the coordinate claims. Specific embodiments are defined in the dependent claims.

The apparatus has a device for monitoring the status of the safety device for the machine, for example a safety switch, which signals the closed state of the safety device, upon which the apparatus provides an enabling signal for the operation of the machine and passes this signal on, for example, to a higher-level machine controller. The machine can be put into operation when the enabling signal is present.

The apparatus according to the invention has a detection device for detecting a locking insert, which locking insert can be operatively connected to the detection device. The locking insert is portable and in particular, can be removed from the detection device without the use of tools. For example, the locking insert can be removed by an operator, and the operator can take the locking insert with them. When the locking insert is removed, no enabling signal is provided by the apparatus; a startup of the machine is thereby reliably prevented. It is irrelevant whether the safety device is closed or not, in particular even when the safety device is in a closed state, the enabling signal is only provided when the locking insert is operatively connected to the detection device.

In one embodiment, a missing locking insert does not otherwise affect the operation of the apparatus, in particular a missing locking insert does not lead to a power down of the apparatus. As a result, the apparatus can still recognize whether the safety device is closed or not, for example. The apparatus can also signal to a higher-level machine controller that, although the safety device is closed, due to the fact that the locking insert has been removed, no enabling signal can be provided.

Such apparatuses may be used, for example in the maintenance of machines and systems. Before the authorized personnel enter the safety zone around the machine or system, the locking insert is disengaged from its operative connection to the detection device and brought into the safety zone, for example by authorized personnel. Should the safety device be closed, a startup of the machine that could pose a hazard to personnel is reliably prevented, since the apparatus provides no enabling signal.

In one embodiment, signal processing and the output of the signal to the apparatus, in particular the detection device, are carried out in accordance with the applicable safety regulations and safety standards. Thus, for example, signal processing may be carried out redundantly via dual channels and/or the output of a signal by the detection device to the apparatus may be carried out via dual channels. If only one of the two channels signals that no operative connection exists between the detection device and the locking insert, no enabling signal is provided.

In one embodiment, the interaction of the locking insert with the detection device is mechanically and electrically independent of the interaction of the components of the device for monitoring the status of the safety device for the machine, in particular independent of the interaction of a switch head and an actuator of a safety switch. Unlike the blocking inserts for mechanically encoded actuators of safety switches, the safety device can be closed independently of whether the locking insert interacts with the detection device or not. Damage to the safety switch as a result of forcibly closing the safety device, despite the fact that the mechanical locking insert is inserted, is thereby excluded.

In one embodiment, the locking insert has a unique identifier that can be sent as a signal to the detection device, and the apparatus only provides the enabling signal when the detection device is in an operative connection to the locking insert, which has an identifier expected by the apparatus. For this purpose, the locking insert can have data memory, in in which a digital code is stored electronically, which can be transmitted to the detection device when there is an operative connection thereto. For example, a code that is multiple bits in length can be stored in memory. The unique identifier preferably cannot be detected without an external electronic tool, thereby increasing the tamper resistance. The encoding of the locking insert may be non-modifiable, for example by using Read Only Memory (ROM) or of Programmable Read Only Memory (PROM). Alternatively, it may also be possible to supplement or overwrite the contents of the memory, and an erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM) or the like may be used.

In one embodiment, the locking insert can be operatively connected to the detection device without an electrical contact. For example, the signals can be transmitted by means of electromagnetic waves, optically, or in another manner, between the locking insert and the detection device.

In one embodiment, the locking insert has a transponder, which responds to an impulse, for example from a reading coil of the detection device, for example by transmitting the code stored in memory. The electrical energy for operating the locking insert can thereby be obtained from an electromagnetic field generated by the detection device. The range of the transponders, or the reading coil, respectively, of the detection device can thereby be less that 20 cm, in particular less than 10 cm and preferably approximately 5 cm, in order to prevent an unintentional readout of the locking insert.

Alternatively or in addition, a sensor may also be disposed on the detection device, which guarantees that the locking insert can only be read out when the locking insert appropriately approaches the detection device, for example when the locking insert is inserted into a receptacle provided therefor on the detection device. To this end, for example, the locking insert may have a permanent magnet, which interacts with a magnetic sensor element, for example a reed switch.

In one embodiment, the detection device has a receiving element for receiving the locking insert. The locking insert can only be operatively connected to the detection device when said locking insert is in a state of having been received in the receiving element. For example, the detection device may have a slit as a receiving element, into which the locking insert can be inserted. The locking insert is preferably releasably fixed in the position provided for the interaction with the detection device, for example by being clamped by means of a securing means.

When the locking insert is inserted, the data of the locking insert, in particular the data in memory, are read out by the detection device and checked for validity. If the inserted locking insert is recognized as valid, the apparatus can provide the enabling signal, subject to any further conditions such as, for example, the detection of the closed safety device. If, however, no locking insert or no valid locking insert is read out, the apparatus will block the provision of the enabling signal. A startup of the machine is therefore only possible when a locking insert is present, and when said locking insert is recognized by the detection device as valid.

In one embodiment, the apparatus has multiple detection devices, and the apparatus only provides an enabling signal when each detection device is operatively connected to a locking insert. Each detection device has at least one expected value in terms of the identifier associated with the locking insert. In one embodiment, it is irrelevant which locking insert acts together with which of the multiple detection devices, as long as the condition that each detection device is operatively connected to a locking insert has been met. It is thereby possible that multiple persons can enter the safety zone of the machine at the same time, and each person may remove one of the blocking inserts and thus reliably prevent a startup of the machine.

In one embodiment, the apparatus signals the status of the operative connection between the locking insert and the detection device and/or the status that no such operative connection exists. The signaling may be carried out vis-á-vis a higher-level machine controller and/or may be done locally, for example, optically and/or acoustically. Thus, for example, a lamp on the apparatus or directly on the detection device can signal the interaction of the detection device with a valid locking insert. For example, a light-emitting diode, which may be multicolored if necessary, can be disposed, which signals, by means of a green or red light, whether or not an operative connection exists with valid locking insert.

In one embodiment, the device for monitoring the status of the safety device has a safety switch comprising a switch head and an actuator, which can be brought into interaction with one another. The actuator may be an electronically encoded actuator, which can be placed in proximity to the switch head switch head of the apparatus in order to interact therewith. The detection device for detecting the locking insert can be constructed such that it is identical to the reader device of the switch head for interaction with the actuator. In particular, both the detection device and the reader device of the switch head may exhibit a redundancy in order to increase safety, in particular a dual-channel signal processing and/or signal output.

The location of the operative connection between the locking insert and the detection device may be placed at a distance from the site of interaction between the actuator and the switch head. For example, the detection device for the locking insert may be placed at a distance from the safety device in order to prevent an unintentional or manipulative removal of the locking insert. For example, the detection device may be disposed in a control cabinet that is at a distance from the safety device.

In one embodiment, the device for monitoring the status of the safety device for the machine also has a retention means for retaining the closed status of the safety device. The retention means may be a mechanical sliding bolt, an anchor plate of an electromagnetic guard control or the like, which prevents an opening of the closed status of the safety device, for example as long as the machine is in operation or in another operational state that poses a hazard to personnel. The retention can only be activated when the locking insert is operatively connected to the detection device. For example, when the locking insert is not inserted, it is impossible to activate the guard control, so that the safety device can be opened at any time.

In one embodiment, the apparatus has a blocking means, by means of which access for the locking insert in a spatial region that enables an operative connection to the detection device can be blocked. In this way, by locking the blocking means, a person entering the safety zone can ensure that no locking insert can be operatively connected to the detection device. For example, a mechanical blocking means can block access to a receptacle of the detection device for the locking insert. The blocking means may be releasably lockable, for example in the position in which the blocking means blocks access for the locking insert. Locking may be effected, for example, by means of a padlock that can be hooked into the blocking means. Multiple locking means may also simultaneously lock the blocking means, so that multiple persons can simultaneously ensure that no locking insert can be placed in an operative connection to the detection device, for example. It is only when the last locking means has been removed that the blocking means can be moved out of its blocking position.

The invention also relates to a locking insert for use in an apparatus as described above. The locking insert is portable and can be operatively connected to a detection device of the apparatus, as well as removed from the detection device, preferably without the use of tools. Due to a code stored in the locking insert, in addition to the function as a locking insert, the selection of one of several modes of operation of the machine can be controlled. Thus, for example, certain modes of operation may only be permitted for authorized personnel. The locking insert must be operatively connected to the detection device in order to select the appropriate mode of operation. To this end, the locking insert may also interact with additional detection devices of the same apparatus or with additional detection devices of additional apparatuses. For example, the locking insert may simply function as a locking insert in the case of the one apparatus, whereas that locking insert may also, or only, function as a switch for selecting a mode of operation in the case of an additional device and, for example, may enable or switch on a set-up mode for the machine.

The invention relates to a method for controlling the operation of a machine having an apparatus as described above. In one embodiment, an interruption of the operative connection between the locking insert and the detection device during operation of the machine does not cause the operation to be interrupted, but instead, the machine may continue to operate with limitations if necessary, and/or for a limited period of time. Nevertheless, restarting the machine after a standstill or another secure condition is only possible when the locking insert is again operatively connected to the detection device. This prevents the removal of the locking insert from leading to an immediate standstill of the machine in the manner of an emergency shutdown function.

Alternatively or in addition, the interruption of the operative connection between the locking insert and the detection device may also be associated with a required entry of a code in order to allow the enabling signal to be effectively blocked. A further alternative is in locking the option of interrupting the operative connection between the detection device and the locking insert, for example as long as the machine in operation. Alternatively or in addition, the locking insert can also be fixed in one position, for example by means of a magnetic force, which position ensures an operative connection with the detection device as long as the machine is in operation.

Further advantages, features and details of the invention arise from the dependent claims as well as the following description, in which multiple embodiments are described in detail with reference to the drawings. In so doing, the features mentioned in the claims and in the description may be essential to the invention, each individually unto themselves, or in any combination.

FIG. 1 shows a top view of a schematically illustrated arrangement of an apparatus according to the invention for controlling the operation of a machine,

FIG. 2 shows a perspective view of the detection device fixed to a front plate,

FIG. 3 shows a perspective view of the essentially disk-shaped locking insert, and

FIG. 4 shows a perspective view of an additional embodiment.

FIG. 1 shows a top view of a schematically illustrated arrangement of an apparatus 1 according to the invention for controlling the operation of a machine 3 having a device for monitoring the status of a safety device 2 for the machine 3, in particular a safety switch for monitoring the closed status of the safety gate or the like of the safety device 2, for example in order to protect the operating personnel from a hazard posed by the machine 3 that is in operation. When the safety device 2 is in a closed state, the apparatus 1 is able to provide an enabling signal for the operation of the machine 3.

The safety device 2 has a first part 4, for example a fixed frame. The first part 4 has an opening 5, which can be closed by a second part 6, for example by a safety gate, which is movably mounted by means of mounting elements 11 and which can be moved relative to the first part 4 in accordance with the double arrow 9; instead of sliding, the safety gate may also be pivoted.

The apparatus 1 has a safety switch, which has a switch element 7 that is preferably disposed on the fixed first part 4 of the safety device 2, which switching element has a switch head 12, and comprises an actuator 8 that is preferably disposed on the movable second part 6, which actuator can be operatively connected to the switch head 12 when the safety gate is closed, and which thereby controls the switch element 7. The switch element 7 can switch the machine 3 on and off either by itself, by means of separate switching elements, or by means of an ancillary or higher-level controller by providing an enabling signal.

In this embodiment, the actuator 8 has a transponder 20, which can interact with the switch head 12 in an electrically contactless manner, which switch head has a reading coil. Interaction is thereby only possible when the safety device 2 is closed. When closing the safety device 2 a switching element is closed by the interaction between the actuator 8 and the switch head 12 for example, and an enabling signal is thereby provided for the operation of the machine 3. When the safety device 2 is opened, the interaction is interrupted, the switching element opened and the machine 3 shut off.

The apparatus 1 may also have a retanong device, by means of which the closed state of the safety device 2 can be releasably locked. The guard control may be realized mechanically, for example by means of a preferably positive locking fixing of the actuator 8 to the switch head 7 by means of a magnetic force or in another suitable manner.

The apparatus 1 has a detection device 10 for detecting a locking insert 14, which locking device can be operatively connected to said detection device 10, is portable, and can be removed from the detection device 10, preferably without the use of tools. When the safety device 2 is in a closed state, the apparatus 1 also only provides the enabling signal when the locking insert 14 is operatively connected to the detection device 10. When the locking insert 14 is removed from the detection device 10, there is no longer an operative connection, so that the apparatus 1 can no longer provide an enabling signal, and therefore the machine 3 cannot be put into operation, regardless of the open or closed status of the safety device 2.

The locking insert 14 interacts with the detection device 10 in an electrically contactless manner, for example with a reading head of the detection device 10, which may be constructed such that it is identical to the reading head 12 of the device for monitoring the safety device 2. In the illustrated embodiment, the detection device 10 is disposed directly on the switch element 7. Alternatively or in addition to this, the detection device 10, or an additional detection device, may also be disposed at a location that is removed from the switch element 7 or the safety device 2, for example in a control cabinet. Access to the detection device 10 may be limited to a definable group of individuals, for example by only being accessible by means of a lockable door of a control cabinet.

FIG. 2 shows a perspective view of the detection device 10 fixed to a front plate 16. The dimensions of the front plate 16 can be adapted to a definable or even a standardized size and thus can be designed as an easily replaceable part of a larger control unit. Multiple identical detection devices 10 may also be disposed on the apparatus 1.

The detection device 10 has a receiving element 30 having a receiving slot 18 for the insertion of the locking insert 14. In the inserted state of the locking insert 14 that is shown, an operative connection exists between the locking insert 14 and a reading head of the detection device 10, which is disposed in a housing 22 and therefore is no longer visible. In this state, data can be exchanged without an electrical contact between the locking insert 14 and the detection device 10, and in particular, a unique code that is stored electronically in the locking insert 14, can be transferred from the locking insert 14 to the detection device. If the locking insert 14 is removed from the receiving slot 18, the operative connection is interrupted and the apparatus 1 does not provide an enabling signal for the operation of the machine 3.

A lamp 24 is disposed on the detection device 10, which in this embodiment is a light-emitting diode, with which it is possible to signal that an operative connection exists between the locking insert 14 and the detection device 10, for example by means of a green light, or that no such operative connection exists, for example by means of a red light.

FIG. 3 shows a perspective view of the essentially disk-shaped locking insert 14. A data memory and a receiver antenna are disposed in a central region 26 such that these are not visible from the outside and are protected against damage and manipulation. An attachment opening 28 is provided in the region of a peripheral, cam-shaped lug 32, with which opening the locking insert 14 can be attached, for example to a key ring.

FIG. 4 shows a perspective view of an additional embodiment. In the state illustrated, access to the receiving slot 18 of the receiving element 30 of the detection device 10 is blocked by a blocking means 32 formed in the embodiment as a sliding bolt, so that no locking insert 14 can be operatively connected to the detection device 10. The blocking means 32 is mounted in two guides 34 fixed on the front plate 16 such that the blocking means can be longitudinally displaced. In the blocking position, the blocking means 32 can be locked by means of a locking means 36, in this embodiment, by means of one or more padlocks. To this end, the blocking means 32 has multiple openings 38, into each of which a locking means 36 can be placed or inserted. For example, ten or more openings 38 for ten or more locking means 36 may be provided. Only when all locking means 36 have been removed, can the blocking means 32 be removed, thereby enabling access for the locking insert 14.

In addition to the detection device 10, an additional detection device 110 is disposed in this embodiment, with which the locking insert 14 can be operatively connected after being removed from the detection device 10. The additional detection device 110 may be essentially identical in its structure to the detection device 10, and in particular may likewise have a receiving element 130 having a receiving slot 118 for the insertion of the locking insert 14 as well as associated signaling means 124. This has the advantage that it is possible to detect the operative connection of the locking insert 14 with the additional detection device 110. For example, after the operative connection of the locking insert 14 with the detection device 10 has been interrupted, a control unit could expect an operative connection with the additional detection device 110 within a definable period of time, or otherwise may emit a signal, for example an acoustic signal, as a reminder to insert the locking insert 14 into the receiving slot 118 of the additional detection device 110. Alternatively or in addition, a simple receptacle for the locking insert 14 may be provided, on which the locking insert 14 may be disposed during the interruption of the operative connection with the detection device 10. The locking insert 14 can also be disposed on the detection device 10 in a captive manner, for example being fixed to the front plate 16 with a chain. 

1. An apparatus (1) for controlling the operation of a machine (3) having a device for monitoring the status of a safety device (2) for the machine (3), in particular a safety switch for monitoring the closed status of the safety gate or the like of the safety device (2), wherein, when the safety device (2) is in a closed state, the apparatus (1) can provide an enabling signal for the operation of the machine (3), characterized in that the apparatus (1) has a detection device (10) for detecting a locking insert (14), which locking insert can be operatively connected to the detection device (10), is portable, and can be removed from the detection device (10) without the use of tools, and that even when the safety device (2) is in a closed state, the apparatus (1) only provides the enabling signal when the locking insert (14) is operatively connected to the detection device (10).
 2. The apparatus (1) according to claim 1, characterized in that the locking insert (14) has a unique identifier, and that the apparatus (1) only provides the enabling signal when the detection device (10) is operatively connected to a locking insert (14), which has an identifier expected by the apparatus (1).
 3. The apparatus (1) according to claim 1, characterized in that the locking insert (14) has an electronic memory, in which a code is stored, which can be read by the detection device (10) when an operative connection exists.
 4. The apparatus (1) according to claim 1, characterized in that the locking insert (14) can be operatively connected to the detection device (10) in an electrically contactless manner.
 5. The apparatus (1) according to claim 1, characterized in that the locking insert (14) has a transponder, which exchanges signals with the detection device, without an electrical contact (10).
 6. The apparatus (1) according to claim 1, characterized in that the detection device (10) has a receiving element (30) for receiving the locking insert (14), and that the locking insert (14) is only operatively connected to the detection device (10) when said locking insert is in a state of having been received in the receiving element (30).
 7. The apparatus (1) according to claim 1, characterized in that the apparatus (1) has multiple detection devices (10), and that the apparatus (1) only provides the enabling signal when each detection device (10) is operatively connected to a locking insert (14).
 8. The apparatus (1) according to claim 1, characterized in that the apparatus (1) signals the status of the operative connection between the locking insert (14) and the detection device (10) and/or the status that no such operative connection exists.
 9. The apparatus (1) according to claim 1, characterized in that the device for monitoring the status of the safety device (2) for the machine (3) comprises a switch head (12) and an actuator (8), which can be brought into interaction with one another, and in that the actuator (8) is an electronically encoded actuator (8), which can be placed in proximity to the switch head (12) of the apparatus (1) in order to interact therewith.
 10. The apparatus (1) according to claim 9, characterized in that a reader device of the switch head (12) for interacting with the actuator (8) and the detection device (10) for detecting the locking insert (14) are constructed identically.
 11. The apparatus (1) according to claim 1, characterized in that the device for monitoring the status of the safety device (2) for the machine (3) also has a retention means for retaining the closed status of the safety device (2), and in that the retention can only be activated when the locking insert (14) is operatively connected to the detection device (10).
 12. The apparatus (1) according to claim 1, characterized in that the apparatus (1) has blocking means (32), by means of which access to the locking insert (14) in a spatial region that enables an operative connection to the detection device (10) can be blocked.
 13. A locking insert (14) for use in an apparatus (1) according to claim 1, characterized in that the locking insert (14) is portable, can be operatively connected to a detection device (10) of the apparatus (1) and can be removed from the detection device (10) without the use of tools, and in that, due to coding stored in the locking insert (14), the selection of one or more modes of operation of the machine (3) can be controlled.
 14. A method of controlling the operation of a machine (3) having an apparatus (1) comprising a device for monitoring the status of a safety device (2) for the machine (3), in particular a safety switch for monitoring the closed status of the safety gate or the like of the safety device (2), wherein, when the safety device (2) is in a closed state, the apparatus (1) provides an enabling signal for the operation of the machine (3), characterized in that the apparatus (1) has a detection device (10) for detecting a locking insert (14), which locking insert can be operatively connected to the detection device (10), is portable, and can be removed from the detection device (10) without the use of tools, and that even when the safety device (2) is in a closed state, the enabling signal is only provided when the locking insert (14) is operatively connected to the detection device (10).
 15. The method according to claim 14, characterized in that, during operation of the machine (3), interrupting the operative connection between the locking insert (14) and the detection device (10) does not interrupt the operation of the machine (3), but that restarting the machine (3) after a standstill or another secure condition is only possible when the locking insert (14) is again operatively connected to the detection device (10). 